JP2004019639A - High pressure fuel pump controller for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-pressure fuel pump controller for an internal combustion engine capable of improving the stability in driving and controlling the high-pressure fuel pump by limiting a termination timing of a control signal driving an actuator within a discharge flow rate controllable range of the high-pressure fuel pump. <P>SOLUTION: In this high-pressure fuel pump controller for the internal combustion engine, the high-pressure fuel pump has a pressure chamber, a plunger for pressing the fuel in the pressure chamber, a fuel passing valve mounted in the pressure chamber, and the actuator for operating the fuel passing valve. The controller has a means for calculating a driving signal of the actuator to make the capacity or pressure of the high-pressure fuel pump variable, and the means for calculating the driving signal has a means for limiting the termination timing of the driving signal of the actuator to a specific phase. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-pressure fuel pump control device for an internal combustion engine, and more particularly to a high-pressure fuel pump control device for an internal combustion engine that can variably adjust a discharge amount of high-pressure fuel that is pressure-fed to a fuel injection valve of the internal combustion engine.
[0002]
[Prior art]
Current automobiles are required to reduce emissions of specific substances such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) contained in automobile exhaust gas from the viewpoint of environmental protection. For the purpose of reducing these, a direct injection engine (a direct injection internal combustion engine) has been developed. The in-cylinder injection internal combustion engine directly injects fuel by a fuel injection valve into a combustion chamber of a cylinder, and promotes combustion of the injected fuel by reducing the particle diameter of fuel injected from the fuel injection valve. In addition, reduction of specific substances in exhaust gas, improvement of engine output, etc. are aimed at.
[0003]
Here, in order to reduce the particle diameter of the fuel injected from the fuel injection valve, a means for increasing the pressure of the fuel is required. Therefore, a high-pressure fuel pump for pumping high-pressure fuel to the fuel injection valve is required. (For example, JP-A-10-153157, JP-A-2001-123913, JP-A-2000-8997, JP-A-11-33638, and JP-A-11-324860). And JP-A-11-324575, JP-A-2000-18130, JP-A-2001-248515 and the like.
[0004]
The technology disclosed in Japanese Patent Application Laid-Open No. H10-153157 aims to improve the fuel supply capacity of a high-pressure fuel supply device for an internal combustion engine. The variable discharge high-pressure pump of the device has three passages in a pump chamber. That is, an inflow passage through which low-pressure fuel flows into the pump chamber, a supply passage through which high-pressure fuel is supplied to the common rail, and a spill passage are communicated. A spill valve is connected to the spill passage, and the spill valve is opened and closed. The discharge amount is adjusted by controlling the spill amount to the fuel tank by the operation. In the technique described in Japanese Patent Application Laid-Open No. 2000-123913, the discharge amount is adjusted by changing the volume of the pump chamber from the start of the suction stroke to immediately before the end of the discharge stroke.
[0005]
The technique disclosed in Japanese Patent Application Laid-Open No. 2000-8997 discloses a technique for reducing the driving force of a high-pressure fuel pump and controlling the flow rate by controlling the flow rate of high-pressure fuel supplied according to the fuel injection amount of a fuel injection valve. If the pressure on the downstream side (pressurizing chamber side) of the suction valve is equal to or higher than the pressure on the upstream side (suction port side) even when the valve does not operate, An engagement member for generating a valve closing force on the suction valve, the engagement member being provided with a biasing force so as to engage when the suction valve moves in the valve closing direction; An actuator for applying a biasing force in the direction to the engagement member is provided, and the amount of fuel discharged is adjusted by opening and closing the suction valve.
[0006]
Further, the technique described in Japanese Patent Application Laid-Open No. 11-336638 is for accurately adjusting the fuel regardless of the operating state of the engine. The opening and closing of the solenoid valve is controlled in synchronism with the pressure feed.
[0007]
Furthermore, the technology disclosed in Japanese Patent Application Laid-Open No. H11-324860 aims at achieving high precision flow control, miniaturization and cost reduction of a variable discharge high pressure pump. The technology disclosed in Japanese Patent Application Laid-Open Publication No. 2000-18130 aims to improve responsiveness when the target pressure changes in a device that variably controls the fuel injection pressure. The discharged fuel is relieved to the suction side by using a normally closed solenoid valve, and the fuel pressure on the fuel injection valve side is controlled to improve reliability.
[0008]
Furthermore, the technology disclosed in Japanese Patent Application Laid-Open No. 2001-248515 discloses a valve opening signal supplied to the normally closed solenoid valve, in order to prevent an abnormal rise in coil temperature from a top dead center to a bottom dead center of a fuel pump plunger. At the predetermined position just above the top dead center during the suction stroke toward.
[0009]
[Problems to be solved by the invention]
By the way, as shown in FIG. 19, the operation timing chart of the conventional fuel pressure control by the variable discharge amount high pressure pump is such that a REF signal 1801 is generated from a cam angle signal and a crank angle signal, and the REF signal 1801 is used as a reference. A solenoid control signal (pulse) 1802, which is an actuator drive signal, is output by angle or time control. Even if the solenoid control signal 1802 ends, current flows through the coil for a while, so that the solenoid maintains the suction force.
[0010]
For example, when a small discharge amount request is made to the pump, the solenoid control signal 1802 is output near the top dead center of the plunger (the details of the control will be described later). At this time, if the suction force of the solenoid is maintained until the next discharge stroke, the pump performs full discharge due to the characteristics of the high-pressure fuel pump.
[0011]
That is, while the high-pressure pump performs a full discharge, the pump requires a small discharge, so that the measured fuel pressure cannot follow the target fuel pressure. As a result, it becomes impossible to realize an optimum fuel pressure under the operating conditions of the internal combustion engine, and stable combustion cannot be obtained due to the adhesion of fuel to the piston surface, and the problem of deterioration of exhaust gas properties occurs. .
[0012]
That is, the present inventor has found that in controlling the variable discharge amount high pressure pump, it is important to know that the timing of ending the solenoid control signal is important. The end timing of the drive signal of the actuator is calculated using at least one of an engine speed, a fuel injection amount from the fuel injection valve, a battery voltage, and a coil resistance, and based on the calculation, before the top dead center of the plunger. New knowledge that it is necessary to limit to
[0013]
However, although each of the above-mentioned conventional techniques describes, for example, controlling the opening / closing timing of a spill valve for adjusting a fuel pressure feed amount to be sent to a common rail by a control device, it is an actuator of a variable discharge amount high pressure pump. There is no indication of the timing of limiting the control signal of the solenoid, and no particular consideration is given to the above.
[0014]
The present invention has been made in view of the above-described problems, and an object of the present invention is to limit the end timing of the control signal of the high-pressure fuel pump to thereby improve the stability of the drive control of the high-pressure fuel pump. An object of the present invention is to provide a high-pressure fuel pump control device for an internal combustion engine that can be improved.
[0015]
[Means for Solving the Problems]
To achieve the above object, a high-pressure fuel pump control device for an internal combustion engine according to the present invention basically includes a fuel injection valve provided in a cylinder, a high-pressure fuel pump that feeds fuel to the fuel injection valve, The high-pressure fuel pump includes a pressurizing chamber, a plunger for pressurizing the fuel in the pressurizing chamber, a fuel-fuel passage valve provided in the pressurization chamber, and an actuator for operating the fuel passage valve. The controller has means for calculating a drive signal of the actuator so as to make the discharge amount or the pressure of the high-pressure fuel pump variable, and the means for calculating the drive signal includes a drive signal of the actuator. And a means for restricting the end timing of the process to a predetermined phase.
[0016]
According to the high pressure fuel pump control apparatus for an internal combustion engine of the present invention configured as described above, the output timing of the drive signal of the actuator that closes the fuel intake passage is within the range of the phase that can reliably control the fuel discharge amount. , The fuel pressure can be controlled optimally and quickly, which can contribute to stabilization of combustion and improvement of exhaust gas performance.
[0017]
In a specific aspect of the high-pressure fuel pump control device for an internal combustion engine according to the present invention, the means for restricting to the predetermined phase restricts the end timing of the drive signal of the actuator to before the top dead center of the plunger. It is characterized by doing.
[0018]
Further, in another specific aspect of the high-pressure fuel pump control device for an internal combustion engine according to the present invention, the means for restricting to a predetermined phase includes: The calculation is performed using at least one of the fuel injection amount from the valve, the battery voltage, and the coil resistance.
[0019]
Still further, in a specific aspect of the high-pressure fuel pump control device for an internal combustion engine according to the present invention, the means for restricting to the predetermined phase uses an electronic circuit, and the driving of the actuator is performed. When the end timing of the signal is limited to the predetermined phase, at least one of a fuel injection amount from the fuel injection valve, a fuel injection timing, and an ignition timing is changed and controlled.
[0020]
The internal combustion engine high-pressure fuel pump control device of the present invention configured as described above, in addition to the end timing of the drive signal of the actuator is limited to the predetermined phase, whether the operation of the internal combustion engine is in stratified combustion, Switching control of combustion of the internal combustion engine can be performed based on whether the pulsation of the fuel pressure is within an allowable value or the like.
[0021]
Another aspect of the high-pressure fuel pump control device for an internal combustion engine according to the present invention includes: a fuel injection valve provided in a cylinder; and a high-pressure fuel pump for pumping fuel to the fuel injection valve. A pressurizing chamber, a plunger for pressurizing the fuel in the pressurizing chamber, a fuel-fuel passage valve provided in the pressurization chamber, and an actuator for operating the fuel-fuel passage valve; In order to make the discharge amount or the pressure of the high-pressure fuel pump variable, a means for calculating a drive signal of the actuator is provided, and the means for calculating the drive signal is such that the output timing of the drive signal of the actuator is a predetermined phase or later Means for not outputting a drive signal in the case, and when the drive signal is not output, the fuel injection amount from the fuel injection valve, the fuel injection timing, and the ignition timing are reduced. It is characterized in that at least one is changed and controlled.
[0022]
In the high-pressure fuel pump control device for an internal combustion engine of the present invention configured as described above, in the control process of the pump control device, the drive request time of the actuator may be longer than the drive time calculated based on operation conditions and the like, In such a case, as the worst condition, the fuel passage valve may not be able to be reliably closed, and the high-pressure pump may not be able to perform pumping, and in consideration of the possibility that the fuel pressure may increase pulsation, Determines that it is impossible to output a drive signal for the actuator, sets the pump phase control signal drive time to 0, and inhibits energization of the solenoid (drive of the actuator).
[0023]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a high-pressure fuel pump control device for an internal combustion engine according to the present invention will be described with reference to the drawings.
[0024]
FIG. 1 shows an overall configuration of a control system for a direct injection internal combustion engine 507 according to the present embodiment. The in-cylinder injection internal combustion engine 507 is composed of four cylinders, and air introduced into each cylinder 507b is taken in from an inlet portion 502a of an air cleaner 502, passes through an air flow meter (air flow sensor) 503, and controls an electronic throttle which controls an intake flow rate. The gas enters the collector 506 through the throttle body 505 in which the valve 505a is housed.
[0025]
The air taken into the collector 506 is distributed to each intake pipe 501 connected to each cylinder 507b of the internal combustion engine 507, and then guided to a combustion chamber 507c formed by a piston 507a, the cylinder 507b, and the like.
[0026]
Further, a signal indicating the intake flow rate is output from the airflow sensor 503 to an internal combustion engine control device (control unit) 515 having the high-pressure fuel pump control device of the present embodiment. Further, a throttle sensor 504 for detecting the opening of the electronically controlled throttle valve 505a is attached to the throttle body 505, and a signal thereof is also output to the control unit 515.
[0027]
On the other hand, fuel such as gasoline is primarily pressurized from a fuel tank 50 by a fuel pump 51 and is supplied to a fuel pressure regulator 52 at a constant pressure (for example, 3 kg / cm 3 ² ) And a higher pressure (for example, 50 kg / cm) by the high-pressure fuel pump 1 described later. ² ), And is injected through a common rail 53 from a fuel injection valve (fuel injection valve) 54 provided in each cylinder 507b into a combustion chamber 507c. The fuel injected into the combustion chamber 507c is ignited by an ignition plug 508 according to an ignition signal whose voltage is increased by an ignition coil 522.
[0028]
A crank angle sensor 516 attached to the crankshaft 507d of the internal combustion engine 507 outputs a signal indicating the rotational position of the crankshaft 507d to the control unit 515, and outputs a cam angle attached to a camshaft (not shown) of the exhaust valve 526. The sensor 511 outputs an angle signal indicating the rotation position of the camshaft to the control unit 515, and also outputs an angle signal indicating the rotation position of the pump driving cam 100 of the high-pressure fuel pump 1 to the control unit 515.
[0029]
Further, an A / F sensor 518 provided upstream of the catalyst 520 in the exhaust pipe 519 detects an A / F of the exhaust gas, and a detection signal thereof is also output to the control unit 515.
[0030]
2, a main part of the control unit 515 includes an MPU 603, an EP-ROM 602, a RAM 604, an I / OLSI 601 including an A / D converter, and the like, and includes a crank angle sensor 516, a cam angle sensor 511, and the like. And taking in signals from various sensors including the internal combustion engine cooling water temperature sensor 517 and the fuel pressure sensor 56 as inputs, executing predetermined arithmetic processing, and outputting various control signals calculated as the arithmetic results, A predetermined control signal is output to the high-pressure pump solenoid 200 as an actuator, each of the fuel injection valves 54, the ignition coil 522, and the like to execute a fuel discharge amount control, a fuel injection amount control, an ignition timing control, and the like. is there.
[0031]
3 and 4 show the high-pressure fuel pump 1. FIG. 3 shows an entire configuration diagram of a fuel system including the high-pressure fuel pump 1. FIG. FIG.
[0032]
The high-pressure fuel pump 1 pressurizes fuel from a fuel tank 50 to pump high-pressure fuel to a common rail 53. The high-pressure fuel pump 1 includes a cylinder chamber 7, a pump chamber 8, and a solenoid chamber 9. 7 is disposed below the pump chamber 8, and the solenoid chamber 9 is disposed on the suction side of the pump chamber 8.
[0033]
The cylinder chamber 7 includes a plunger 2, a lifter 3, and a plunger lowering spring 4. The plunger 2 is pressed against a pump driving cam 100 that rotates with the rotation of the cam shaft of an exhaust valve 526 in the internal combustion engine 507. Reciprocating through the lifter 3 changes the volume of the pressurizing chamber 12.
[0034]
The pump chamber 8 includes a suction passage 10 for low-pressure fuel, a pressurized chamber 12, and a discharge passage 11 for high-pressure fuel. A suction valve 5 is provided between the suction passage 10 and the pressurized chamber 12. The suction valve 5 is a check valve that restricts the fuel flow direction via a valve closing spring 5a that urges the pump chamber 8 toward the solenoid chamber 9 in the valve closing direction. A discharge valve 6 is provided between the pressurizing chamber 12 and the discharge passage 11, and the discharge valve 6 is also urged from the pump chamber 8 toward the solenoid chamber 9 in the valve closing direction of the discharge valve 6. This is a check valve that restricts the flow direction of the fuel through the closing valve spring 6a. The pressure of the pressurizing chamber 12 is equal to or greater than the pressure of the inflow passage 10 across the suction valve 5 due to the change in the volume of the pressurizing chamber 12 due to the plunger 2. In this case, the suction valve 5 is urged to close.
[0035]
The solenoid chamber 9 includes a solenoid 200 as an actuator, a suction valve engaging member 201, and a valve opening spring 202. The tip of the suction valve engaging member 201 can be freely connected to and separated from the suction valve 5. It is disposed at a position opposite to the suction valve 5 and is moved in a direction to close the suction valve 5 by energizing the solenoid 200. On the other hand, when the solenoid 200 is de-energized, the suction valve engaging member 201 moves in a direction to open the suction valve 5 via a valve opening spring 202 engaged with the rear end, and The suction valve 5 is opened.
[0036]
The fuel whose pressure has been adjusted to a constant pressure from the fuel tank 50 via the fuel pump 51 and the fuel pressure regulator 52 is led to the suction passage 10 of the pump chamber 8, and thereafter, the fuel is compressed by the pressurizing chamber 12 in the pump chamber 8. Pressurized by the reciprocating motion of the plunger 2, the pressure is sent from the discharge passage 11 of the pump chamber 8 to the common rail 53.
[0037]
The common rail 53 includes a fuel injection valve 54 provided in accordance with the number of cylinders of the internal combustion engine 507, a relief valve 55, and a fuel pressure sensor 56. A control unit 515 includes a crank angle sensor 516, The drive signal of the solenoid 200 is output based on the detection signals of the angle sensor 511 and the fuel pressure sensor 56 to control the fuel discharge amount of the high-pressure fuel pump, and the drive signal of each fuel injection valve 54 is output. To control the fuel injection. In addition, the relief valve 55 is opened when the pressure in the common rail 53 exceeds a predetermined value to prevent breakage of the piping system.
[0038]
FIG. 5 shows an operation timing chart of the high-pressure fuel pump 1. The actual stroke (actual position) of the plunger 2 driven by the pump driving cam 100 is a curve as shown in FIG. 6, but in order to make the positions of the top dead center and the bottom dead center easy to understand, The stroke of the plunger 2 is represented linearly.
[0039]
Next, a specific operation of the high-pressure fuel pump 1 will be described with reference to an operation timing chart of FIG.
[0040]
When the plunger 2 moves from the top dead center side to the bottom dead center side in response to the urging force of the plunger descending spring 4 due to the rotation of the cam 100, the suction stroke of the pump chamber 8 is performed. In the suction stroke, the position of the rod serving as the suction valve engaging member 201 is engaged with the suction valve 5 in accordance with the urging force of the valve-opening spring 202 to move the suction valve 5 in the valve opening direction. The pressure in the chamber 12 decreases.
[0041]
Next, when the plunger 2 moves from the bottom dead center side to the top dead center side against the urging force of the plunger descending spring 4 due to the rotation of the cam 100, the compression stroke of the pump chamber 8 is performed. In the compression stroke, when a drive signal (ON signal) of the solenoid 200 as an actuator is output from the control unit 515 and the solenoid 200 is energized (ON state), the position of the rod serving as the suction valve engaging member 201 is changed. The suction valve 5 is moved in the valve closing direction against the urging force of the valve opening spring 202, and the tip thereof is disengaged from the suction valve 5 so that the suction valve 5 is attached to the valve closing spring 5a. By moving in the valve closing direction according to the force, the pressure in the pressurizing chamber 12 increases.
[0042]
When the suction valve engaging member 201 is most attracted to the solenoid 200 side and the suction valve 5 synchronized with the reciprocating motion of the plunger 2 closes and the pressure in the pressurizing chamber 12 increases, the pressure in the pressurizing chamber 12 increases. Presses the discharge valve 6, the discharge valve 6 opens automatically against the urging force of the valve-closing spring 6a, and the high-pressure fuel corresponding to the reduced volume of the pressurizing chamber 12 moves to the common rail 53 side. Discharged. When the suction valve 5 is closed on the solenoid 200 side, the drive signal of the solenoid 200 is turned off (OFF state). However, as described above, the pressure in the pressurizing chamber 12 is reduced. Since it is high, the suction valve 5 is maintained in the closed state, and fuel is discharged to the common rail 53 side.
[0043]
Further, when the plunger 2 moves from the top dead center side to the bottom dead center side according to the urging force of the plunger descending spring 4 by the rotation of the cam 100, the suction stroke of the pump chamber 8 is performed, and the pressurizing chamber is moved. As the pressure in the valve 12 decreases, the suction valve engaging member 201 is engaged with the suction valve 5 in response to the urging force of the valve opening spring 202 and moves in the valve opening direction. The valve is automatically opened in synchronization with the reciprocation, and the open state of the suction valve 5 is maintained. The discharge valve 6 is not opened because the pressure in the pressurizing chamber 12 is reduced. Thereafter, the above operation is repeated.
[0044]
For this reason, when the solenoid 200 is turned on during the compression process before the plunger reaches the top dead center, the fuel pressure feeding to the common rail 53 is performed from this time, and the fuel pressure feeding is started. Once started, since the pressure in the pressurizing chamber 12 has increased, even if the solenoid 200 is subsequently turned off, the suction valve 5 maintains the closed state while synchronizing with the start of the suction process. The valve can be automatically opened, and the amount of fuel discharged to the common rail 53 can be adjusted by the output timing of the ON signal of the solenoid 200. Further, the control unit 515 calculates an appropriate energization ON timing based on the signal of the pressure sensor 56 and controls the solenoid 200, whereby the pressure of the common rail 53 can be feedback-controlled to a target value.
[0045]
FIG. 7 is a control block diagram of the high-pressure fuel pump 1 performed by the MPU 603 of the control unit 515 having the high-pressure fuel pump control device. The high-pressure fuel pump control device includes a basic angle calculation unit 701, a target fuel pressure calculation unit 702, a fuel pressure input processing unit 703, and a unit for calculating a drive signal of the solenoid 200 as one embodiment. Means (actuator drive signal calculation means) 1502.
[0046]
The basic angle calculating means 701 calculates a basic angle BASANG of a solenoid control signal for turning on the solenoid 200 based on the operation state, and outputs the calculated basic angle BASANG to the pump control signal calculating means 1502. FIG. 8 shows the relationship between the closing timing of the suction valve 5 and the discharge amount of the high-pressure fuel pump. As can be understood from FIG. 8, the basic angle BASANG is determined by the required fuel injection amount and the high-pressure fuel pump discharge amount. The angle at which the suction valve 5 closes is set so that the amounts are balanced.
[0047]
The target fuel pressure calculation means 702 similarly calculates a target fuel pressure Ptarget optimal for the operating point based on the operating state and outputs the target fuel pressure Ptarget to the pump control signal calculation means 1502. The fuel pressure input processing means 703 filters the signal of the fuel pressure sensor 56, detects the measured fuel pressure Preal, which is the actual fuel pressure, and outputs it to the pump control signal calculation means 1502.
[0048]
Then, the pump control signal calculation means 1502 calculates the solenoid control signal, which is an actuator drive signal, based on the signals, and outputs the calculated signal to the solenoid drive means 707, as described later.
[0049]
FIG. 9 shows a timing chart of the operation of the control unit 515 (including the high-pressure fuel pump control device). The control unit 515 detects a top dead center position of each piston 507a based on a detection signal (CAM signal) from the cam angle sensor 511 and a detection signal (CRANK signal) from the crank angle sensor 516, and controls fuel injection and ignition. In addition to performing timing control, a stroke of the plunger 2 of the high-pressure fuel pump 1 is detected based on a detection signal (CAM signal) from the cam angle sensor 511 and a detection signal (CRANK signal) from the crank angle sensor 516. The solenoid control which is the fuel discharge control of the fuel pump 1 is performed. The REF signal, which is a basic point of the solenoid control, is generated based on the CRANK signal and the CAM signal.
[0050]
Here, the portion where the signal of the CRANK signal is missing (shown by a dotted line) in FIG. 9 is a reference position, and is a predetermined phase from the top dead center of CYL # 1 or the top dead center of CYL # 4. It is out of position. Then, when the signal of the CRANK signal is missing, the control unit 515 determines whether the signal is on the CYL # 1 side or the CYL # 4 side depending on whether the CAM signal is Hi or Lo. The discharge of the fuel from the high-pressure fuel pump 1 is started after a lapse of a predetermined time corresponding to the operation delay of the solenoid 200 from the rise of the solenoid control signal, while the discharge is pressurized even when the solenoid control signal ends. Since the suction valve 5 is pressed by the pressure from the chamber 12, the plunger stroke is continued until it reaches the top dead center.
[0051]
FIG. 10 is a control block diagram specifically showing the pump control signal calculation means 1502 of the present embodiment. The pump control signal calculating means 1502 basically includes a reference angle calculating means 704 for calculating the timing of the ON signal of the solenoid 200 and a pump signal energizing time calculating means 706 for calculating the width of the ON signal. The calculating means 704 is based on the basic angle BASANG of the basic angle calculating means 701, the target fuel pressure Ptarget of the target fuel pressure calculating means 702, and the measured fuel pressure Preal of the fuel pressure input processing means 703, based on a reference for starting the output of the ON signal. A reference angle REFANG is calculated.
[0052]
Then, the output start angle STANG of the ON signal of the solenoid 200 is calculated by adding the operation delay correction amount PUMRE by the solenoid operation delay correction unit 705 to the reference angle REFANG, and the solenoid drive unit 707 is used as the timing of the ON signal of the solenoid 200. Output.
[0053]
Further, the pump signal energization time calculation means 706 calculates the energization request time TPUMKEMAP of the solenoid 200 of the high-pressure fuel pump 1 based on the operating conditions. The value of the energization request time TPUMKEMAP is determined by the suction valve engaging member until the suction valve 5 can be closed by the pressure of the pump chamber 2 even under the worst condition of generating the solenoid suction force, where the battery voltage is low and the solenoid resistance is large. A value that allows the intake valve 5 to be closed without fail is set. On the other hand, the energization time maximum value calculation means block 710 calculates an energization time maximum value TPUMKEMAX for preventing the attraction force of the solenoid from being maintained until the next discharge stroke. The minimum value selection unit 709 selects the minimum value of the power supply request time TPUMKEMAP and the power supply time maximum value TPUMKEMAX, and outputs the selected value to the solenoid driving unit 707 as the power supply time TPUMKE. That is, the upper limit of the energization request time TPUMKEMAP is set to the energization time maximum value TPUMKEMAX.
[0054]
Then, the solenoid 200 is driven based on the output start angle STANG and the energization time TPUMKE. Here, the solenoid operation delay correction unit 705 calculates the solenoid operation delay correction based on the battery voltage because the electromagnetic force of the solenoid 200, and thus the operation delay time varies depending on the battery voltage.
[0055]
Next, a specific description of the first embodiment of the energization time maximum value calculation means 710 will be given. The absolute signal end phase calculation means 708 calculates an angle OFFANG from a basic point (REF signal) where the energization signal must be absolutely turned off. Even if the signal which started the energization in the high-pressure pump discharge stroke is kept ON until the pump suction stroke, the energization in the suction stroke in this case does not contribute to the closing of the suction valve. The angle OFFAMG from the point (REF signal) is set to be equal to or less than the angle from the basic point to the plunger top dead center. In addition, an angle at which the attraction force of the solenoid after the energization signal is turned off is not maintained until the next ejection stroke is set.
[0056]
FIG. 11 is a diagram showing a relationship between the solenoid control signal (energization signal), the energization current value, and the attraction force of the solenoid. After the energization signal is turned off, a current flows through the solenoid for a certain period, and The suction force is maintained until it falls below the value. This period depends on the coil resistance and the battery voltage. Further, since the phase control is performed, it is necessary to input the number of rotations in order to convert the period into the unit of angle. That is, the angle OFFANG from the basic point (REF signal) is calculated using at least one of the coil resistance, the battery voltage, and the rotation speed.
[0057]
FIG. 12 shows the relationship between the output start angle STANG, the angle OFFANG from the basic point (REF signal), and the maximum energization time TPUMKEMAX. The difference between the angle OFFANG from the basic point (REF signal) and the output start angle STANG becomes the energization time maximum value TPUMKEMAX.
[0058]
FIG. 13 shows a second embodiment in the energization time maximum value calculation means 710. The energization time maximum basic value calculation means 711 calculates the energization time maximum basic value from the output start angle STANG obtained from the fuel injection amount, the engine speed, the fuel pressure, and the like, and the engine speed. The maximum energizing time is calculated by multiplying the basic value of the energizing time by the battery voltage correction coefficient calculated by the battery voltage correcting means 712, and is output to the minimum value selecting section 709.
[0059]
FIG. 14 shows the pump control signal calculating means 1502 of the second embodiment of the present invention. The difference from the pump control signal calculating means 1502 of the first embodiment is that the minimum value selecting section 709 (FIG. (See FIG. 2) is provided with an energization time calculation unit 713. The energization time calculation means 713 calculates the energization time TPUMKE based on the TPUMKEMAP calculated by the pump signal energization time calculation means 706 and the TPUMKEMAX calculated by the energization time maximum value calculation means 710, and outputs the calculated energization time TPUMKE to the solenoid drive signal. is there.
[0060]
FIG. 15 shows a control flow in the energization time calculation means 713. In step 3001, interrupt processing is started. The interruption process may be a time cycle such as every 10 ms or a rotation cycle such as every 180 degrees of the crank angle. In step 3002, the energization request time TPUMKEMAP and the energization time maximum value TPUMKEMAX are read. In step 3003, the magnitude relation between the energization request time TPUMKEMAP and the energization time maximum value TPUMKEMAX is determined. If the energization time maximum value TPUMKEMAX is larger, the pump phase control signal energization time TPUMKE = TPUMKEMAP is output. On the other hand, when the energization time maximum value TPUMKEMAX is smaller, it is determined that the energization request time TPUMKEMAP cannot be output, and the energization to the solenoid is prohibited by setting the pump phase control signal energization time TPUMKE = 0.
[0061]
In the processing by the pump control signal calculating means 1502, the energization request time TPUMKEMAP of the solenoid 200 may be larger than the energization time TPUMKE. In this case, the suction valve may not be able to be reliably closed under the worst condition for generating the solenoid suction force, and the pump may not be able to perform pumping due to the failure to close the suction valve reliably, which may increase the pulsation of the fuel pressure. There is.
[0062]
FIG. 16 shows a control flow in a case where the pump cannot perform pumping and the fuel pressure may pulsate.
In step 3101, an interrupt process is started. The interruption process may be performed at a time period such as every 10 ms or at a rotation period such as every 180 degrees of the crank angle. In step 3102, the energization request time TPUMKEMAP and the energization time TPUMKE are read. In steps 3103 to 3105, when it is determined that the energization time TPUMKE is shorter than the energization request time TPUMKEMAP, the stratified combustion operation is performed, and there is a possibility of misfire due to pulsation, the uniformity which is strong against the fluctuation of the fuel pressure is determined. Shift to combustion operation.
[0063]
FIG. 17 shows parameters such as the output start angle STANG of the solenoid control signal and the energization time TPUMKE for the control of the fuel pressure by the control unit 515. The pump control signal calculation means 1502 of the present embodiment shown in FIG. FIG. 4 is a diagram specifically illustrating the control of FIG. The output start angle STANG, which is the output timing of the ON signal of the solenoid 200, can be obtained as in the following equation (1).
[0064]
(Equation 1)
STANG = REFANG-PUMRE (1)
[0065]
Here, the reference angle REFANG is calculated by the reference angle calculation means 704 (FIG. 10) based on the operating state of the internal combustion engine 507. PUMRE is a pump delay angle, which is calculated by the solenoid operation delay correction means 705 (FIG. 10), and indicates, for example, an actuator drive time that changes depending on the battery voltage, that is, an operation delay of the suction valve engagement member 201 based on solenoid energization. ing.
[0066]
Next, the pump phase control signal energizing time TPUMKE, which is the width of the ON signal of the solenoid 200, is calculated based on the operating state using the pump phase control signal energizing time calculating means 706 as a basic value (FIG. 10). Then, based on the output start angle STANG, how long from the basic point, which is the rise of the REF signal, the ON signal of the solenoid 200 for closing the suction valve 5 is output, that is, the output timing of the solenoid control signal is obtained. On the other hand, how long the solenoid control signal is continuously output, that is, the width of the solenoid control signal, is determined based on the pump phase control signal energizing time TPUMKE.
[0067]
The high-pressure fuel pump control device according to the present embodiment basically supplies power for the time calculated from the calculated solenoid control signal output timing, and supplies the pump phase control signal when the signal end timing exceeds a predetermined value. There is a time limit. As described above, the embodiment of the present invention has the following functions based on the configuration.
[0068]
The control unit 515 of the present embodiment is a high-pressure fuel pump control device for a direct injection internal combustion engine 507 having a fuel injection valve 54 provided in a cylinder 507b and a high-pressure fuel pump 1 for pumping fuel to the fuel injection valve 54. Wherein the high-pressure fuel pump 1 includes a plunger 2 for pressurizing the fuel in the high-pressure fuel pump 1, a solenoid 200 that is phase-controlled to change the discharge amount or pressure of the high-pressure fuel pump 1, A suction valve 5 for closing the fuel suction passage 10 by an ON signal of the solenoid 200; the control device includes a pump control signal calculating means 1502; and the pump control signal calculating means 1502 Means for restricting the output timing of the OFF signal of the solenoid 200 to within a range of a predetermined phase. The high pressure fuel pump 1 is prevented from discharging an unintended amount of fuel, and the fuel pressure can be controlled optimally and promptly, thereby stabilizing combustion. And exhaust gas performance can be improved.
[0069]
FIG. 18 is an operation timing chart of the high-pressure fuel pump control device of the present embodiment.
According to the present embodiment, the target fuel pressure can be reliably controlled by managing the energization signal end timing. By reliably controlling the fuel pressure to the target fuel pressure, misfire and adhesion of fuel in the cylinder can be prevented, thereby contributing to reduction of exhaust gas.
[0070]
As described above, the two embodiments of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments, and various designs may be made without departing from the spirit of the present invention described in the appended claims. It can be changed.
[0071]
For example, in the above-described embodiment, the high-pressure fuel pump 1 is disposed on the camshaft of the exhaust valve 526, but is disposed on the camshaft of the intake valve 514 or synchronized with the crankshaft 507d of the cylinder 507b. May be.
[0072]
Further, as a method of limiting the energization signal end timing, a method may be used in which the plunger position of the high-pressure fuel pump is used as a switch input and the energization signal is ended by an electronic circuit when the plunger rises near top dead center.
[0073]
Further, in the above-described embodiment, the suction valve of the high-pressure fuel pump is operated by a solenoid (actuator) to adjust the pressure of the pressurizing chamber of the pump. The present invention is not limited to this, and the present invention can be implemented with another fuel passage valve that is disposed between the pressurizing chamber of the pump and the outside of the pump and communicates and passes fuel. The fuel passage valve may be a release valve for releasing fuel in the pressurized chamber of the pump, in addition to the suction valve. In the case of the relief valve, the manner of operation by a solenoid (actuator) is specifically different from that of the suction valve. However, in implementing the invention described in the claims of the present application. Are the same.
[0074]
【The invention's effect】
As understood from the above description, the high-pressure fuel pump control device for an internal combustion engine according to the present invention limits the end timing of the solenoid control signal to within a predetermined phase range, so that the fuel pressure is optimized, and Control can be performed quickly, and deterioration of exhaust gas properties can be prevented.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a control system for an internal combustion engine including a high-pressure fuel pump control device according to an embodiment of the present invention.
FIG. 2 is an internal configuration diagram of the control device for the internal combustion engine of FIG. 1;
FIG. 3 is an overall configuration diagram of a fuel system including the high-pressure fuel pump of FIG. 1;
FIG. 4 is a longitudinal sectional view of the high-pressure fuel pump of FIG. 3;
FIG. 5 is an operation timing chart of the high-pressure fuel pump of FIG. 3;
FIG. 6 is a supplementary explanatory diagram of the operation timing chart of FIG. 5;
FIG. 7 is a basic control block diagram of the high-pressure fuel pump control device of FIG. 1;
FIG. 8 is a view showing a discharge flow rate characteristic in the high-pressure fuel pump of FIG. 3;
FIG. 9 is a basic operation timing chart of the high-pressure fuel pump control device of FIG. 1;
FIG. 10 is a control block diagram of a pump control signal calculation means of the high-pressure fuel pump control device of FIG. 7;
FIG. 11 is a diagram showing a relationship between a solenoid control signal and a suction force in the high-pressure fuel pump of FIG. 3;
FIG. 12 is a supplementary explanatory diagram of a pump control signal calculation means of the high-pressure fuel pump control device of FIG. 10;
FIG. 13 is a basic control block diagram of another embodiment of the energization time maximum value calculating means of the high pressure fuel pump control device of FIG. 10;
FIG. 14 is a control block diagram of a pump control signal calculating means of the high-pressure fuel pump control device according to another embodiment of the present invention.
FIG. 15 is an operation flowchart of the high-pressure fuel pump control device of FIG. 10;
FIG. 16 is a diagram showing a control flow in a case where the pump cannot perform pumping and the fuel pressure may pulsate in the control device for an internal combustion engine according to each embodiment of the present invention.
FIG. 17 is a basic operation timing chart of the high-pressure fuel pump control device of FIG. 10;
FIG. 18 is an operation timing chart at the time of fuel pressure control of the high-pressure fuel pump control device of FIG. 10;
FIG. 19 is an operation timing chart at the time of fuel pressure control of a conventional high-pressure fuel pump control device.
[Explanation of symbols]
1 High pressure fuel pump
2 plunger
5 Suction valve
11 Inhalation passage
54 fuel injection valve
200 Actuator (solenoid)
507 In-cylinder injection internal combustion engine
507b cylinder
515 High-pressure fuel pump control unit (control unit)
701 Actuator basic angle calculation means
702 Target fuel pressure calculation means
703 Means for calculating actual fuel pressure (fuel pressure input processing means)
704 Actuator reference angle calculation means
705 Actuator operation delay correction means
706 Means for calculating width of actuator drive signal (pump signal energization time calculation means)
707 Means for driving actuator (solenoid driving means)
708 Power-on time maximum value calculation means
713 Energization time calculation means
1502 Pump control signal calculation means (actuator drive signal calculation means)

Claims (7)

A high-pressure fuel pump control device for an internal combustion engine, comprising: a fuel injection valve provided in a cylinder; and a high-pressure fuel pump that pumps fuel to the fuel injection valve,
The high-pressure fuel pump has a pressurized chamber, a plunger that pressurizes fuel in the pressurized chamber, a fuel-fuel passage valve provided in the pressurized chamber, and an actuator that operates the fuel passage valve,
The control device includes a unit that calculates a drive signal of the actuator so as to make the discharge amount or the pressure of the high-pressure fuel pump variable, and the unit that calculates the drive signal includes an end timing of the drive signal of the actuator. A high-pressure fuel pump control device for an internal combustion engine, comprising: means for restricting the pressure to a predetermined phase. 2. The high-pressure fuel pump control device for an internal combustion engine according to claim 1, wherein the means for limiting to the predetermined phase limits the end timing of the drive signal of the actuator before a top dead center of the plunger. The means for restricting to the predetermined phase calculates the end timing of the drive signal of the actuator using at least one of an engine speed, a fuel injection amount from the fuel injection valve, a battery voltage, and a coil resistance. The high-pressure fuel pump control device for an internal combustion engine according to claim 1 or 2, wherein: The high-pressure fuel pump control device for an internal combustion engine according to claim 1, wherein the means for limiting the phase to the predetermined phase uses an electronic circuit. The method according to claim 1, wherein when the end timing of the drive signal of the actuator is limited to the predetermined phase, at least one of a fuel injection amount, a fuel injection timing, and an ignition timing from the fuel injection valve is changed and controlled. 2. The high pressure fuel pump control device for an internal combustion engine according to claim 1. A high-pressure fuel pump control device for an internal combustion engine, comprising: a fuel injection valve provided in a cylinder; and a high-pressure fuel pump that pumps fuel to the fuel injection valve,
The high-pressure fuel pump has a pressurized chamber, a plunger that pressurizes the fuel in the pressurized chamber, a fuel-fuel passage valve provided in the pressurized chamber, and an actuator that operates the fuel-fuel passage valve,
The control device has means for calculating a drive signal of the actuator so as to make the discharge amount or the pressure of the high-pressure fuel pump variable, and the means for calculating the drive signal includes an output timing of the drive signal of the actuator. A high-pressure fuel pump control device for an internal combustion engine, comprising: means for not outputting a drive signal when the control signal is after a predetermined phase. 7. The high-pressure fuel pump for an internal combustion engine according to claim 6, wherein when the drive signal is not output, at least one of a fuel injection amount, a fuel injection timing, and an ignition timing from the fuel injection valve is changed and controlled. Control device.

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